When Reducing Transmission Is Not Enough: Carrier Dynamics and Backward Bifurcation in Influenza-Pneumococcal Co-infection

Bacterial co-infection, particularly with \emph{Streptococcus pneumoniae}, is a major driver of morbidity during influenza epidemics, and this burden falls disproportionately on sub-Saharan Africa, where both pathogens circulate year-round at high levels and pneumococcal carriage remains common and